Gas spring on swivel chair

The term “gas spring” is very unfamiliar. It refers to a kind of hardware, and it is also called “air pressure rod” or “air support”. It is actually very close to us. For many office workers, they keep a “close distance” with it almost every day.
Where is it? Look down. If you are sitting on a computer chair or office chair that can be rotated and adjusted in height, and the chair has a height-adjustable handle, then it is there, right under the chair surface. In a thick shaft in the middle, this low-key hardware that we hardly know has attracted more and more attention in recent years, because the news of “swivel chair explosions hurting people” has continued to spread, making people even more worried about sitting on pins and needles: It is simply sitting on a “time bomb”.

To put it simply, a gas spring is like an engine cylinder. A closed pressure tube is filled with high-pressure nitrogen and oil, or a mixture of oil and gas. The pressure in the tube is higher than atmospheric pressure to push the piston and piston rod to move. The cross-section of the piston rod is smaller than the cross-section of the piston to generate a pressure difference, that is, an elastic force. The elasticity can be set by setting different nitrogen pressures or piston rods of different diameters.

In fact, gas spring technology began to be industrialized by Western industrial countries around the 1930s, and gradually expanded from door and window accessories to medical equipment, automobiles, textile equipment, and processing industries, such as the opening of the front and rear covers of modern cars. At present, gas springs are also divided into many professional categories. The use of gas springs to adjust the height of the seat is a technology that has only appeared in the past ten years. This type of gas spring is called a self-locking gas spring, which can generate a large locking force. It is this force that allows the chair to be raised and lowered at will while bearing the weight, which is much more convenient than the swivel chair that was adjusted by rotation many years ago. Now, some chairs can freely adjust the tilt angle of the cushion and the pitch angle of the backrest with the help of gas spring technology, so as to ensure that the shape of the seat conforms to the ergonomic curve to the greatest extent.

But if the internal space of the gas spring is inferior in material and not tightly sealed; or the purity of the gas in the pressure chamber is not enough, frequent rises and falls will cause the temperature and pressure of the pressure chamber to rise sharply, and there is a hidden danger of explosion. Those injuring seats use low-strength materials, or use high-pressure air instead of nitrogen with a purity of more than 90%.

Post time: Aug-29-2020